We highly recommend that you buy these fully compatible with ADSL / MaxDSL / ADSL2 / ADSL2/2+. These Heavy duty are designed for higher usage and higher bandwidth especially If your ADSL Line is 2MB or above .
A micro filter or ADSL Filter, separates your analogue telephone service from the data signals used on your broadband service, allowing you to use both simultaneously. It will help you get better voice quality. Although our filters may be at a fraction of many other on the market, but this does not mean we compromise on the quality. All our ADSL filters are of very high quality and according to BT specifications. It Meets all SIN346 requirements including 'longitudinal balance' test.
Manufactured to exceed the BT SIN 346 v2.2 guidelines for UK microfilters. It offers complete compatibility with BT services such as CLI (Caller ID). Manufactured for maximum compatibility with even the most complex telephone equipment. Fully compatible with DECT cordless phones and PABX systems.

How many ADSL filters do I need?
You will need to fit an ADSL filter to every telephone outlet where a telephone is connected. Whilst there is no practical limit to the number of filters that can be connected to a phone line, we recommend a maximum of four filters and that the phone should be connected to a filtered sockets only unless the phones's socket has built in filter components. It is possible to attach a 'phone-doubler' adapter to a filter in order to attach two telephone handsets. However it is important to note that not filtering one telephone device will affect other devices and this may stop all the other filters working correctly.

Specification
Applied in voice or data transmission circuits
Provides isolated conversion between modem and telephone line
Have filter function,and passed UK test standard
Single DC Resistance :<=50 ohm
Insertion loss :1KHz;<1dB
Attenuation distortion :200Hz
Return loss from phone side <200Hz
Input port: UK plug*1
Output Jack: US Jack (for modem)*1
UK Jack (for phone)*1
Dimension: 58*43*23.1 mm; wire length: 100±5mm

Material & Color
Box: ABS (W13)
Wire: PVC (F353)
1.8 uF Ring Capacitor.

Frequency range
Splitter band with: DC to 16 KHz
Nominal voice band: 0.3 KHz to 3.4 KHz